876-03-9

1877-72-1

876-03-9

Step 6 Synthesis of 3-(aminomethyl)benzoic acid hydrochloride: 3-cyanobenzoic acid (5.88 g, 40 mmol) was suspended in 50 mL of tetrahydrofuran (THF), stirred and heated gently until completely dissolved. Subsequently, 50 mL of isopropanol was added and the solution was cooled to room temperature. To the cooled solution, 4.2 mL of pre-cooled concentrated hydrochloric acid was slowly added, followed by 300 mg of platinum(IV) oxide catalyst. The reaction mixture was subjected to hydrogenation under 55 psi hydrogen pressure overnight. Upon completion of the reaction, 50 mL of ether was added to precipitate the product, the precipitate was collected by filtration and washed with ether. The resulting solid was dissolved in methanol, filtered to remove the catalyst, and finally the solvent was removed by distillation under reduced pressure to afford 6.2 g (82% yield) of the target product 3-(aminomethyl)benzoic acid hydrochloride. The structure of the product was confirmed by 1H-NMR (DMSO-d6): δ = 4.08 (d, 2H); 7.53 (t, 1H); 7.80 (d, 1H); 7.94 (d, 1H); 8.10 (s, 1H); 8.65 (s, 3H).